Side-by-side fluid cartridges (also known as dual-compartment cartridges or multi-component cartridges) are used for storing two viscous fluids separately within a single container unit and dispensing the fluids simultaneously so that they may be mixed and applied to a common substrate. Traditional side-by-side cartridges consist of a pair of cylindrically-shaped fluid chambers positioned adjacent and parallel to one another. Each chamber is configured to store a viscous fluid and includes an inlet at which the chamber is filled with the fluid, and an outlet from which the fluid is later dispensed. For example, the side-by-side cartridge may be used to store and dispense a two-part epoxy, where one chamber stores and dispenses the resin and the other chamber stores and dispenses the hardener. The fluid chambers may have equal internal volumes or different internal volumes as desired depending on the particular fluids being dispensed and their corresponding mixing ratios, for example a 1:1 mixing ratio or a 2:1 mixing ratio.
Fluid dispensing devices are used in conjunction with fluid cartridges, including side-by-side cartridges, for dispensing the stored fluid in precise amounts with repeatable accuracy. Traditional dispensing devices for side-by-side fluid cartridges include a dispenser body to which a side-by-side cartridge is attachable, and two pistons positioned side by side and each mounted on a plunger rod for extending the pistons from the dispenser body. In use, each piston is coaxially aligned with one of the fluid chambers of the fluid cartridge so that the pistons may extend into the fluid chambers to force the stored fluid out through the outlets of the cartridge. However, traditional fluid dispensing devices for use with side-by-side fluid cartridges present several drawbacks.
First, when attaching a side-by-side fluid cartridge to a traditional dispensing device, the cartridge must be moved from a first, assembly position into a second, dispensing position, for example by rotating or tilting the cartridge relative to the dispensing device. In the assembly position, the pistons are not aligned with the fluid chambers and thus are not extendable into the fluid chambers. Once the fluid cartridge is moved into the dispensing position, each piston is axially aligned with a corresponding fluid chamber of the cartridge and the dispensing device is ready for use. In this manner, the pistons are extendable and retractable within the fluid chambers of the side-by-side cartridge only when the cartridge has been moved from the assembly position into the dispensing position. Moreover, the side-by-side cartridge cannot be moved back to the assembly position for removal of the cartridge until the pistons have first been fully retracted from each of the fluid chambers. Attempting to move the cartridge from the dispensing position to the assembly position while the pistons are still extended into the fluid chambers would result in damaging the pistons and/or the plunger rods to which they are mounted. Accordingly, an operator must fully retract the pistons from the fluid chambers before removing the cartridge from the dispensing device. This step can become burdensome when using multiple consecutive cartridges in a dispensing application.
An additional drawback of traditional dispensing devices for side-by-side fluid cartridges relates to compatibility of the dispensing device with fluid cartridges having different flange thicknesses. Side-by-side fluid cartridges include a cartridge flange near the chamber inlets that engages the dispenser body when the cartridge and dispensing device are locked together in the dispensing position. Traditional dispensing devices include mating surfaces that are formed to accommodate only side-by-side cartridges having a cartridge flange of a particular thickness. Cartridge manufacturers often design their cartridges with a flange thickness that differs from that of cartridges produced by other manufacturers. Accordingly, an operator of a traditional dispensing device is generally restricted to use of cartridges produced by a particular manufacturer.
There is a need, therefore, for a fluid dispensing device for side-by-side fluid cartridges that addresses the present challenges such as those discussed above.